Can I disconnect the fan on side door of a computer case

"People worry a lot about heat buildup in systems, but the average consumer does not stress his or her computer to the point that cooling is a big issue. It that were the case you would most likely be a gaming enthusiast and would not be asking the question. I think intel did a nice job investigating the truth of heat/dust and equipment failure rates in a study that is summarized here:

http://www.datacenterknowledge.com/archives/2008/09/18/intel-servers-do-fine-with-outside-air/

In our engineering department we routinely test our circuits under extremem conditions with heat guns and dry ice and while performance will vary, we rarely see any lasting effects.

So go a head and disconnect the fan, because chances are you will want/need a newer and faster computer long before the tiny bit of heat buildup has done any dammage."

"I agree that if the fan is noisy you should consider replacing it with a properly functioning one. However, are you sure that the noise is coming from the side intake fan? I mean no offense if you are sure, I only mention it because in the past I have misidentified the source of fan noise.

Being right next to your video card, it may be the fan on your video card that gets loud as it ramps up under load and the sound just comes out the adjacent vent.

You can disconnect the side fan for a short period of time and verify that the noise goes away. With as many other fans as that case has you'll be fine for the time it takes to test. But @Molly is correct, you should use some kind of software to monitor the temperature of the card with the fan connected and again with it disconnected to determine the actual difference.

Airflow is critical to extending the life of your computer's expensive components. It will save you money in the long run to replace noisy fans with quality replacements."